Procurement measures

Ordered value — the sum over purchase order lines of what was ordered, converted to your book currency. Its document-currency twin adds the orders up as written, in their own currencies.
Open PO value — what is still to come in. Line by line: the order's value less the received share, the received share prorated by quantity received over quantity ordered. An order fully received contributes nothing; an order untouched contributes its whole value.
Received value — the value of posted goods receipt lines, at the receipt cost the posting itself computed, including the effect of goods received but not yet invoiced (see the Procurement chapter). Landed value isolates the landed-cost share riding inside that received value — the freight-and-duty portion — so you can see how much of your stock's cost is carriage rather than goods.
Supplier spend — the sum of net amounts on posted purchase invoice lines, tax excluded; debit notes subtract. This is what you actually committed to pay suppliers, and it differs from received value exactly where invoicing and receiving disagree.
Average lead days — order date to receipt date, averaged over the receipt lines that carry a lead time.
Purchase price variance — on goods received but invoiced later, the difference between the price the invoice finally charged and the cost recorded at receipt: the price element of the clearing. FX variance is its sibling — the portion of that same difference caused purely by the exchange rate moving between receipt and invoice. Between them, a cleared GRNI balance explains itself completely: price, or currency, or nothing left over.